Our Electronic Timed-delay Unit Trapped Key Interlock Switches are used in applications that require an elapsed time to occur before allowing access to a hazardous area. This interlock switch uses a SI Guardmaster® safety relay in combination with an EMD Guardmaster safety relay to execute the timing sequence. Turning a non-removable key initiates the timer. When the EMD times out, its output energizes an internal solenoid which then allows the removal of either one or two trapped keys.
Prosafe Electronic Time Delay Unit Installation Instructions